Full-open end closure provided with distortion resistant shoulder in countersink wall

ABSTRACT

An end closure with a large, removable central panel, an opening tab, a score line about the periphery of the panel and a countersink wall about the periphery of the panel. The countersink wall is provided with an inwardly stepped shoulder along the major portion of its circumferential distance about the panel, but along the minor portion of the countersink wall, diametrically remote from the tab, no inwardly stepped shoulder is provided, resulting in a construction in the end closure which resists upward distortion, during opening of the closure, of the lower portions of the countersink wall along the minor portion thereof.

United States Patent La Croce [451 A r. 11 1972 [54] FULL-OPEN END CLOSURE PROVIDED 3,490,643 1/1970 Henning et al ..220/54 WITH DISTORTION RESISTANT P E G T H H nmary xammereorge a SHOULDER IN COUNTERSINK WALL Attorney-Robert P. Auber, George P. Ziehmer, Ronald A. [72] Inventor: Leonard Thomas La Croce, Paramus, NJ. Schapira and Leonard R. Kohan [73] Assignee: girpril-ican Can Company, Greenwich, [57] ABSTRACT An end closure with a large, removable central panel, an [221 Sept 1970 opening tab, a score line about the periphery of the panel and [21 Appl. No.: 73,930 a countersink wall about the periphery of the panel. The countersink wall is provided with an inwardly stepped shoulder along the major portion of its circumferential distance about the panel, but along the minor portion of the countersink wall, [58] i 250/54 48 27 diametrically remote from the tab, no inwardly stepped o shoulder is provided, resulting in a construction in the end closure which resists upward distortion, during opening of the [56] Reerences Cited closure, of the lower portions of the countersink wall along the UNITED STATES PATENTS mm)! P' Zundeh ..220/54 5 Claims, 7 Drawing Figures PATENTEDMR 11 m2 3, 655,091

2;! 23g INVENTOR.

24/ 2 2 LEONARD THOMAS LA caoca ATTORNEY FULL-OPEN END CLOSURE PROVIDED WITH DISTORTION RESISTANT SHOULDER IN COUNTERSIN K WALL BACKGROUND OF THE INVENTION The can making industry'has been tending toward the increasingly wider use of self-opening cans, designed to be opened by means of an opening tab, secured to a scored, removable section of a can end. One form of these cans has been the full-open" can in which substantially the whole of the metal, top end panel of the can is removable. These fullopen" cans have been well suited for packaging products such as beverages, processed and frozen fruits and vegetables and other comestibles, such as coffee, candy and nuts.

In one form of the full-open can, the removable section is defined by an endless score line disposed about the periphery of the top end panel, and the opening tab is secured to the removable section by a rivet at a point which is close to the score line so that the user can pull upwardly on one end of the opening tab to cause its other end to move downwardly and exert a downward force at or near the outer edge of the end panel to initiate the rupture of the score line. Thereafter, continued upward and backward pulling on the opening tab causes further tearing of the metal in the score line on both sides of the area of initial rupture and effects the eventual, complete detachment of the removable section from the can. See, particularly, my U.S. Pat. No. 3,409,166.

In the just described form of full-open can, the construction of the end closure has included an annular, countersink wall extending upwardly from the top end panel to an outwardly extending flange. The countersink wall has included an annular shoulder, spaced above the tab and adapted to prevent the tab from interfering with the chuck used to seam the end closure on to the top of the can.

It has been found, however, that under certain circumstances, with prior art end closure constructions, the lower portion of the countersink wall has tended to be insufficiently resistant to upward distortion from forces exerted thereon when the opening tab is subjected to the continued upward and backward pulling required to completely detach the removable section from the can. Located in this lower portion of the countersink wall is an annular rough edge developed by the tearing of the residual score line material. Particularly, when on occasion, the can is improperly opened, the lower portion of the countersink wall has tended to be distorted upwardly and radially inwardly away from the can wall, to a position where its rough edge is exposed. This condition could cause a problem to the user of the contents of a full-open can.

One solution to this problem has involved the use of a plurality of beads in the removable section which extend in a direction generally transversely of the longitudinal axis of the opening tab. See my U.S. Pat. No. 3,430,802.

This solution has not proven entirely satisfactory in that a small portion of the lower countersink wall, located generally, diametrically remote from the opening tab, has continued to pose somewhat of a problem for users of the full-open can. In this minor area of the lower countersink wall, the opening tab and hence the removable section is pulled, during opening of the can, against the residual material in the score line in a generally vertical direction with respect to the top end of the can, in order to detach the removable section from the can. It has been noted that in this area of generally vertical pulling, where the lower countersink wall continues to be prone to upward distortion to expose its rough edge, a means is needed for reinforcing the end closure against the upward distortion of its countersink wall.

SUMMARY OF THE INVENTION In order to provide reinforcement for the end closure as described in the Background of the Invention, this invention relates to an end closure which includes:

an inwardly stepped shoulder in the countersink wall which extends for a major, first circumferential distance along the countersink wall and which divides the countersink wall into a lower countersink wall and an upper countersink wall; and

a reinforcing portion of the lower countersink wall, extending for a minor, second circumferential distance along the countersink wall and diametrically remote from the opening tab, which portion is vertically colinear with the upper countersink wall;

the combination of the first circumferential distance of the shoulder and the second circumferential distance of the restraining portion of the lower countersink wall circumscribing substantially 360 about the central, removable section of the end closure.

Numerous other advantages of the invention will be apparent as it is better understood from the following description, which, taken in connection with the accompanying drawing, discloses a preferred embodiment thereof.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a plan view of a full-open, end closure for a can made in accordance with the present invention.

FIG. 2 is an enlarged, sectional view taken along line 22 in FIG. 1.

FIG. 3 is an enlarged, sectional view taken along line 3-3 in FIG. 1.

FIG. 4 is an enlarged, sectional view, similar to FIG. 3 showing the countersink wall after detaching the removable section of the end closure from the can.

FIG. 5 is an enlarged, sectional view, similar to FIGS. 3 and 4 showing the upward distortion of the lower countersink wall in the prior art at a location on the countersink wall diametrically remote from the opening tab.

FIG. 6 is an enlarged, plan view of a full-open, end closure for a can made in accordance with a modified embodiment of the present invention.

FIG. 7 is an enlarged, sectional view taken along line 77 of FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENT As a preferred or exemplary embodiment of the instant invention, FIGS. 1 and 2 show a full-open, end closure, generally 10. The end closure 10 includes: a central, removable panel 12; a score line 14 adjacent to the periphery of the panel 12; an opening tab 16 secured to the panel 12 adjacent to the score line 14; an annular countersink wall, generally 18, extending upwardly from the periphery of the panel 12; and an annular flange 20, extending outwardly from the top of the countersink wall 18. The end closure 10 also includes a plurality of beads 22 in the panel 12 for preventing the upward bowing of the panel 12 and the consequent distortion of the countersink wall 18 during the opening of the end closure, as

- disclosed in U.S. Pat. No. 3,430,802. The end closure further includes, as shown in my pending U.S. application, Ser. No. 728,518, filed May 13, 1968: a rivet 24 for securing the tab 16 to the panel 12; and a combination of an ancillary score 26 and a pair of flex inducing scores 28 in the panel 12 for promoting the tearing of the score 14 and the venting of the can (not shown).

As further shown in FIG. 2, the end closure 10 of FIG. 1 may be seamed on to the wall 30 of a can by forming the outwardly extending flange 20 of the end closure 10 into a conventional double-seam with an outwardly extending flange 32 of the can wall 30.

As still further shown in FIGS. 1 and 2, the countersink wall 18 of the end closure 10 is provided with an inwardly stepped shoulder 34 which extends along the countersink wall 18 for a major portion A, about 338, of the walls circumferential distance about the panel 12. However, as shown in FIGS. 1 and 3, along a minor portion B, about 22, of the walls l8 circumferential distance about the panel 12, the shoulder is not provided. Hereinafter, this major distance A along the countersink wall 18, along which distance the shoulder 34 extends, will be referred to as the first circumferential distance A and the minor distance B along the countersink wall 18, along which distance the shoulder 34 does not extend will be referred to as the second circumferential distance B. As will become clear from the discussion of the preferred embodiment, the angular relationship between the first and second circumferential distances is considered very important to the instant invention.

As shown in FIGS. 2 and 3, the shoulder 34 divides the countersink wall 18 into an upper countersink wall 36 and a lower countersink wall, generally 37. In FIG. 2, the first cir cumferential distance A along the countersink wall 18 is shown wherein the upper countersink wall 36 is located adjacent to the can wall 30 and the lower countersink wall 37 is somewhat spaced inwardly from the can wall 30. Henceforth, the portion of the lower countersink wall 37 which extends for the first circumferential distance A will be called the first lower countersink wall 38. In FIG. 3, the second circumferential distance B along the countersink wall 18 is shown wherein both the upper and lower countersink walls 36, 37 are located adjacent to the can wall 30, except for an inwardly extending residual portion 39 of the lower countersink wall 37. Henceforth, the portion of the lower countersink wall 37 which extends for the second circumferential distance B will be called the second lower countersink wall 40.

It should be noted that the residual portion 39 of the lower countersink wall 37 extends for the full circumferential distance 360 along the countersink wall 18 and connects the countersink wall 18 to the periphery of the panel 12 along the score line 14. Of course, residual portion 39 represents the practical minimum amount of metal which is needed to provide the score 14 adjacent to the countersink wall.

As shown in FIG. 4, the panel 12 has been removed from the end closure of the instant invention. The inwardly extending residual portion 39 of the countersink wall 18 has an exposed, rough edge 42 formed from the torn residual metal of the score line 14. The residual portion 39 of the countersink wall 18 is not projecting upwardly, where the rough edge 42 would be liable to cut the hand of the consumer of the cans contents. Rather, the residual portion 39 is projecting substantially horizontally whereby the rough edge 42 is not a threat to a consumers hand.

By comparison with the prior art (analogous elements in the prior art having their reference numerals greater by 100 than the reference numerals of the preferred embodiment 10 of the instant invention), removing a panel 112, from an end closure 110, as shown in FIG. 5, as caused the residual portion 139, of lower countersink wall 137, to project upwardly due to distortion of the countersink wall 118. It is believed that the lower countersink wall 137, under certain circumstances, is caused to project upwardly due to bending distortion at its annular shoulder 134, resulting from the upward pull of the panel 112, acting through the moment arm formed by the lower countersink wall 137 and the annular shoulder 134. The result, therefore, in the prior art, when improperly opened, of detaching the panel 112 from the end closure 110, is an upwardly projected rough edge 142, along a minor portion of the distance along the countersink wall 118.

From the vertical, sectional view of FIG. 3, it can be seen that the second lower countersink wall 40 is vertically colinear with the upper countersink wall 36. It is this spatial relationship which provides the end closure of the instant invention with reinforcement against upward distortion of its countersink wall in an area diametrically remote from the tab 16.

As an alternative embodiment of the end closure 10 of the instant invention, FIG. 6 shows a portion of a full-open end 210 provided with a modified, second lower countersink wall 240. It should be appreciated that modified end closure 210 is provided with all the aforementioned elements of the original end closure except as may be hereinafter specifically noted (analogous elements of the alternative embodiment having their reference numerals greater by 200 than the reference numerals of the preferred embodiment 10 of the instant invention).

The modified, second lower countersink wall 240 consists of a plurality of undulations or corrugations, the outwardly extending peaks 241 of which are located substantially adjacent to the can wall 230. Thus, the upper countersink wall 236 is vertically colinear with the peaks 241 of the second lower countersink wall 240.

It should be noted, finally, that in both the original and modified embodiments of the inventions the angular relation between the major, first and minor, second circumferential distances A, B along the countersink wall 18 along which the first and second lower countersink walls 38, 40 and 238, 240 extend respectively is in'fact 338 for the first distance A and 22 for the second distance B, their total being 360.

It should also be noted that transitional portions, generally 44 and 244, have been provided between the portions of the lower countersink walls 37, 237 of the embodiments of the invention. The extent of these transitional elements 44, 244 is relatively minor, however, in comparison with the first and second circumferential distances A, B, and for this reason, these portions 44, 244 need not be considered separately but may rather be considered as parts of either the first or second lower countersink walls 38, 40 and 238, 240. However, it should be appreciated that, in actuality, it is the total of the first and second countersink walls 38, 238 and 40, 240 and of the transitional portions 44, 244 which respectively comprise the annular, countersink walls 18, 218 of the end closures 10,

It should further be noted that the centers of the second lower countersink walls 40, 240 are located substantially diametrically remote from the location of the nose of the tab 16 on the score line 14. It is in this location where the second lower countersink walls 40, 240 serve as means for restraining upward, bending distortion of the lower countersink walls 37, 237 relative to the upper countersink wall 36, 236. Also, by this placement, the shoulders 34, 234 provide support for a seaming chuck along the major portion A of the circumferential distance along the countersink walls 18, 218 without interference of the chuck with the opening tab 16.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description and it will be apparent that various changes may be made in the form, construction and arrangement of the parts without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the form hereinbefore described being merely a preferred embodiment thereof.

What is claimed is:

1. In an end closure for a can which includes a central, removable panel, a score line adjacent to the periphery of the panel, an opening tab secured to the panel adjacent to the score line, and an annular, countersink wall extending upwardly from the periphery of the panel, the improvement which comprises:

An inwardly stepped shoulder in the countersink wall which extends for a major, first circumferential distance along the countersink wall and which divides the countersink wall into a lower countersink wall and an upper countersink wall; and

means in the lower countersink wall which extends for a minor, second circumferential distance along the countersink wall, for restraining upward, bending distortion of the lower countersink wall relative to the upper countersink wall as the panel is pulled upwardly with respect to the countersink wall;

said restraining means being positioned substantially diametrically remote from the location of the tab adjacent the score line and the combination of said first circumferential distance of said shoulder and said second circumferential distance of said restraining means about the countersink wall circumscribing substantially 360 about the panel.

2. The end closure of claim 1 wherein said second circumferential distance corresponds to about 22 about the panel.

3. The end closure of claim 2 wherein said restraining means comprises a vertically linear portion of the lower countersink wall which is substantially vertically colinear with the upper countersink wall.

means comprises an undulating portion of the lower countersink wall, the peaks of the undulating portions being vertically linear and substantially vertically colinear with the upper countersink wall. 

1. In an end cLosure for a can which includes a central, removable panel, a score line adjacent to the periphery of the panel, an opening tab secured to the panel adjacent to the score line, and an annular, countersink wall extending upwardly from the periphery of the panel, the improvement which comprises: An inwardly stepped shoulder in the countersink wall which extends for a major, first circumferential distance along the countersink wall and which divides the countersink wall into a lower countersink wall and an upper countersink wall; and means in the lower countersink wall which extends for a minor, second circumferential distance along the countersink wall, for restraining upward, bending distortion of the lower countersink wall relative to the upper countersink wall as the panel is pulled upwardly with respect to the countersink wall; said restraining means being positioned substantially diametrically remote from the location of the tab adjacent the score line and the combination of said first circumferential distance of said shoulder and said second circumferential distance of said restraining means about the countersink wall circumscribing substantially 360* about the panel.
 2. The end closure of claim 1 wherein said second circumferential distance corresponds to about 22* about the panel.
 3. The end closure of claim 2 wherein said restraining means comprises a vertically linear portion of the lower countersink wall which is substantially vertically colinear with the upper countersink wall.
 4. The end closure of claim 1 wherein said restraining means comprises a vertically linear portion of the lower countersink wall which is substantially vertically colinear with the upper countersink wall.
 5. The end closure of claim 1 wherein said restraining means comprises an undulating portion of the lower countersink wall, the peaks of the undulating portions being vertically linear and substantially vertically colinear with the upper countersink wall. 